Friday, March 27, 2009

Segway Transporter Uses Novotechnik Sensor

The steering system of the two-wheeled Segway Personal Transporter (PT) utilises an angular position sensor from Novotechnik to aid balance and acceleration of the vehicle. The second-generation PT is a self-balancing transportation device with sophisticated motion and stabilisation technology that uses the rider's natural body movements to propel and steer the vehicle.

The vehicle can hit 12.5mph and covers a range of 24 miles. The Segway PT uses its Leansteer steering system to allow the riders body movement to guide the vehicle, while the Segway Smart Motion (SSM) controller uses the same information to maintain motion and direction with complete dynamic stability through its balance sensor assembly (BSA), which has integral solid-state rate gyro and tilt sensors.

In operation, the rider simply moves forwards, backwards and to each side to propel and steer the PT in the corresponding direction while the control system ensures that bumps, camber or uneven slopes, which may affect the riders body position, are fully compensated to ensure completely smooth operation. To guarantee the safe operation of the PT and maintain its total reliability, long life and costs, the choice of components are of paramount importance.

The Leansteer system uses the compact and robust SP2880 angular position sensor from German manufacturer Novotechnik, represented exclusively in the UK and Ireland by Variohm Eurosensor. The SP2800 is located at the pivoting base of the handlebar shaft, providing high-bandwidth angular position feedback that effectively measures the rider's body angle, which is used as a reference to generate the lateral acceleration required to balance the PT and its rider.

For this application, the conductive plastic technology SP2880 sensor is a fully redundant design for maximum reliability featuring two completely independent measuring systems, each with precious metal wipers and dual voltage outputs. The sensor provides a 140deg electrical range with a resolution of less than 0.01deg, linearity to +/- 0.3 per cent and repeatability of 0.03deg.

The 28mm-diameter sensor is 17mm long, built from temperature resistant plastic and features a push-on shaft coupling and slotted flange mounting. The durable housing is IP65 rated for dust and water spray protection and has an operating temperature range of -40 to +150C, allowing its use in extreme weather conditions.

The rated life is over 50 million cycles and with a current consumption of less than 1mA, the SP2880 sensor satisfies the requirements for minimal energy use on the battery-powered Segway PT. The Novotechnik 2880 series is a part of a wide range of contacting and non-contacting angular position sensors available from Novotechnik that are stocked and fully supported in the UK by Variohm Eurosensor.

No comments: